Electric protective apparatus.



PATENTED JULY 4, 1905.

F. R. PARKER. v ELECTRIC PROTECTIVE APPARATUS.

APPLICATION PILED,JULY 9. 1904.

m m w m ill! llillll! vlllllllllllllffllllIllllllliif'llilli UNITEDSTATES Patented July 4;, 1905.

PATENT ()FFICE.

FREDERICK R. PARKER, OF CHICAGO, ILLINOIS, ASSIGNOR TO FRANK B.

COOK, OF CHICAGO, ILLINOIS.

ELECTRIC PROTECTIVE APPARATUS.

SPECIFICATION forming part of Letters Patent No. 793,802, dated July 4,1905.

Application filed July 9. 1904. Serial No. 215,933.

To all whom/712$ may concern..-

Be it known that I, FRED ERICK R. PARKER, a citizen of the UnitedStates, residing at Chicago, in the county of Cook and State ofIllinois, have invented new and useful Improvements in ElectricProtective Apparatus, of which the following is a full, clear, concise,and exact description, reference being had to the accompanying drawings,forming a part of this specification.

My invention relates to apparatus used in connection with protectivedevices for electric circuits, my object being, first, to simplify suchapparatus; second, to provide improved means for testing the protectivedevices and circuits through the apparatus without'removing any of theprotective devices from their operative positions; third, to provide animproved arrangement for closing an alarmcircuit when a protectivedevice operates; fourth, to provide improved means for transposingcertain connection-terminals to respective opposite sides of thesupporting-plate, and, fifth, to provide an economical, eflicient, anddurable construction in such apparatus which may be readily and cheaplymanufactured.

The apparatus of this invention is for the purpose of supporting andoperating two classes of electric protective devicesnamely, those whichprotect electrical circuits and apparatus from high-tension electricdischarges, such as lightning, and those which protect said circuits andapparatus from small sneak-currents. The high-tension electricdischarges are guarded against by means of lightningarresters,preferably consisting of carbon blocks with interposed dielectrics, andthe sneak-currents are guarded against by means of heat-coils or thermalprotectors.

This apparatus comprises spring-supports provided with suitable contactsand arranged for holdingthe lightning-arresters and heatcoils, the saidsprings being suitably mounted on a plate which is preferably secured toan iron supporting-frame and conductively connected to earth. When thisapparatus is used in connection with telephone systems to provideprotection therefor, the said springs form terminals for the lines,switchboard, and alarm circuits. When a thermal protector operates, itthrows a ground on certain springs of the combination and controls analarm-circuit anda switchboard-circuit.

I also provide a testing-plug, to be used in connection with theprotective apparatus, the said plug being provided with spring-contactmembers adapted to engage the respective springs of the protectiveapparatus for testing the several circuits through the latter.

I will now describe my invention in detail by reference to theaccompanying sheet of drawings, illustrating same, in which Figure 1 isa plan view of one form of the invention, showing similar parts uponopposite sides of a center line, the apparatus being in duplicate andfor a metallic circuit. Fig. 2 is a side view of Fig. 1, showing severalsets of the protective apparatus mounted side by side. Fig. 3 is a topend view of Fig. 1, showing one set of the protective apparatus. Fig. 4is a view of the protective apparatus,

taken the same as Fig. 1, showing a testing-W plug connected therewithfor testing purposes and another arrangement for controlling thealarm-circuit. Fig. 5 is a view of still another arrangement forcontrolling the alarm-circuit, taken the same as Fig. 1, with a smallportion shown in cross-section. Fig. 6 is a perspective view of aportion of the alarm-spring of Fig. 1, and Fig. 7 is a perspective viewof the common alarm-strip of Fig. 5.

Like characters refer to like parts in the several figures.

The supporting-plate, upon which the protective apparatus is mounted, iscomposed of two metallic strips A A, preferably of brass, preferablyriveted together at B and formed substantially as shown. Each strip A isprovided with projecting points C C thereon, formed out of the strip andadapted to hold the lightning-arresters P P in place therebetweenagainst said strip. This said mounting-plate is adapted to carry aseries of sets of the protective apparatus and is preferably groundedthrough the iron framework of a distributing-board or the like. Theusual form of supporting-plate for protective apparatus now in use is asolid iron bar of considerable thickness, about three-eighths of aninch, to one edge of which is secured a thin strip for supporting thelightning-arresters. This form of plate is very heavy and contains muchunnecessary material. The strips A A of my present invention are verythin, preferably .032 of an inch, and are formed so as to take the placeof both the said usual si.1 ')porting plate and strip secured thereto,thus simplifying the construction and doing away with the larger part ofthe material and weight of the solid-bar form. Another advantage of mystrip A over the solid bar is that the latter has to be drilled wherevera hole therethrough required, while all of the holes of my strip A maybe punched. This is a considerable saving in the manufacture of same.The strips A A maybe nickel-plated over the surfaces against which theligl'itningarresters rest or where c ntact-points make contact to insuregood contact with the contacting parts. Strips A A are similar, thusmaking the mounting-platc reversible. This grouml-platc A A forms thesubject-matter of my copending ain'ilication for Letters latent, SerialNo. QMAOI, liled November 26, 1904:, which is a division of this presentapplication.

The protective devices and springmcmbers of the protective apparatus aremounted in a series of duplicate sets upon the grouml- 'ilate A A, eachduplicate set forming a pair and the sets of each pair being mounted onopposite sides of the said plate directly opposite each other. As theduplicate sets of apparatus of the series are similar to each other, Iwill describe in detail one duplicate set only of the series.

On each side of the ground-plate A A is mounted a pair of springs 11*]and (1i by two double-ended bolts S and T, which extend through thestrips A A near the rear edge of the latter. These springs E and G aremounted liatwise on the said strips and are insulated from each otherand from the said strips by suitable insulating bushings and washeps RR, threaded on the bolts S and T. I preferably place a bushing l) on thesaid bolts between the strips A A, so that when the nuts on S and T arescrewed up tightly the strips A A will be rigidly held at a givendistance from each other. Each spring (aiis provided with ears J Jthereon, between which a heatcoil or thermal protector L is placed andheld by the springn'essiu'e of the said ears, with a hole through whicha contact member N freely passes and with a narrow portion 0 at the freeend thereof, adapted to lit in a groove of a lightning-arrester P, andthereby hold same in place against the strip Q. Springs G G terminate insuitable connection-terminals Y and Z, respectively, and are preferablyto be connected with the hue conductors of a me- 1 tallic line---as, forexample, the limbs of a telephone-line. Each spring E is provided with atongue I near its free end, adapted to ena thermal protector L with ahole therein through which an insulating-pin I-[ is inserted and with anopening I at its free end, adapted to receive a contact member of atesting-plug. Springs E E tern'iinate in suitable connection-terminals Uand \V, respectively, and are preferably to be connected with theconductors of a metallic circuit leading to a central-stationswitchboard. Between each pair of springs (1 and E is placed a thirdspring F, Fig. 1, mounted llatwise on the plate A A by the said bolts Sand T and suitably insulated from the said pair of springs andground-plate. This third spring is preferably an alarm-circuit spring,is provided with contacts M M, Fig. 6, at its free end adapted to makecontact with line-spring (:i when depressed toward the plate A, and witha projecting contact point N, adapted to pass th rough line-spring G andmake contact with the ground-plate A A when the spring F is thusdepressed, as shown on the righthand side of Fig. l. Springs F Ftm'minate in suitable connection-terminals V and X, respectively, andare each preferali ly to be connected with a grounded alarmcircuit. Anumber of springs F F of the strip of protective apparatus may beconnected in common and then connected to a singlealarn1eir euit in amanner well understood, so that the operation of any one of the springsthus connected will close the said alarm-circuit, and thereby operatethe alarm. The circuit from a switchboard-eomluctor to a correspondingline conductor through the protective apparatus is fromconnection-terminal U, through switclrhoard-spring l1], tongue I,thermal protector L, ears J J, line-spring U, and connection-terminal Z,or through a similar circuit on the opposite side of plate A A.

If a high-potential electric current or dis charge, such as lightning,comes to the protective apparatus from a line conductor, it will passthrough a connection-terminal Z or Y and a line-spring (i and then jumpthrough a lightning-arrester P from one carbon block to the other to theground-strip Q, and thence to earth, thus dissipatingits energy withoutin juring the thermal protector L or the switchboard-oircuitandapparatus connected thereto.

When an abnormally-large current with in suflicient voltage to arethrough the lightningarrester, this current being generally termed asneak current, traverses the circuit through a thermal protector L for ashort length of timesay fifteen or twenty seconds--it causes the latterto allow the spring member 1. to operate the said protector L in anysuitable manner, and thereby cause same to release the spring member I,which, with spring 1), takes the position shown on the right of Fig. 1,due to the tension in springs E and I, and thereby opens the circuitthrough the thermal protector L. When spring E is thus operated, itcauses the insulatingpin II to press against the alarm-spring F,

and thereby depress the latter until contacts M M thereof engage theline-spring G and be again engaged with the said device, as

shown upon the left of Fig. 1, which engagement restores the protectiveapparatus to its initial operative position.

I have preferably shown a thermal protector or heat-coil Lof theself-soldering type which is provided with a series of teeth therearoundadapted to turn upon an axis when a fusible material normally holdingthe teeth against rotation is softened by an abnormal current traversingthe said protector; but I do not wish to limit this invention to thisparticular protector.

I preferably transpose certain ones of the connection-terminals toopposite sides of the mounting-plate A A by bending same, as shown at Wand Z, thereby putting both switchboard-terminals U and W on one side ofthe said plate and both line-terminals Y and Z on the opposite side ofthe said plate. It has been the usual practice heretofore when it wasdesired to transpose the connecti'onterminals to connect the springmembers to be transposed with respective auxiliary connection-terminalson opposite sides of the mounting-plate from the said springs either bysoldering separate conductors from each springto acorresponding terminalor through the mountingb'olts, which were properly insulated from eachother and from the said plate, the latter being so thick that it was notthought to be practicable to make the transpositions as I do in-mypresent invention. These methods necessitated many extra parts,

such as terminals, insulating-bushings, and

that the construction of the apparatus is greatly simplified.

In Fig. 4: I have shown a testing-plug adapted to cooperate with theprotective apparatus for testing purposes. The said plug comprises ablock of insulating materialA preferably hard rubber, on opposite endsof which are mounted respective series of contactsprings B C and Dinsulated from each other and adapted to cooperate with the protectiveapparatus, the springs on one end of block A being similar to andforming pairs with the respective springs on the other tacts betweentheportions I I of springs FE and the toothed members L L of the thermalprotectors L L, respectively, as shown in Fig. 4, after which springs Cengage the respective thermal protectors L L, preferably as shown. Oneach end of the testing-plug spring members B and C slightly divergetoward their free ends at the parts thereof which engage the protectiveapparatus when the plug is inserted for testing, and thereby'tend tohold the plug in place after it has been inserted and not allow same tobe easily displaced. The aperturesl I in springs E E and the grooves inthe lightning-arresters all tend to hold the plug in place againstlateral displacement. Springs D 1) are loosely held 'to block A atthcirfree ends by pins 0 and when the testing-plug is connected with theprotective apparatus as described springs I) D engage the'lightning-arresters P P in respective grooves in the latter and restagainst the end portions 0 O of line-springs G Gr, respectively, thuslimiting the insertion of the plug into the protective apparatus.Conductors 1, 2, 3, 4, 5, and 6 lead from the respective springs of thetest-plug to any suitable switch and testing instrument. Thearrangements heretofore employed for testing protective apparatus weresuch that the circuit-protectors had to be removed from their supportsbefore the test-plug could be insertedfor testing or there wereprovided. extra contact members to form normally closed socket-switchesadapted to receive the'testingplug. In my present invention I do notemploy any extra contact members to' form switches for the test-plug nordo I remove any of the circuit-protectors from their sup ports intesting the several circuits through the apparatus. I simply employ thelinesprings and switchboard-springs and the protective devicesthemselves, substantially as shown and described.

The circuits to be tested are as follows: first,

from conductors '1, and (3, through s nings I; B, respectively, springsE E, connection-terminals U and NV, and the switcliboard-circuitconnected to U and \V; second, from conductors 2 and 5, through springs(1" C respectively, thermal protectors L L, ears J J, springs (i (i,connection-torminals Z and Y, and the line-circuit connected to Z and Y;third, from conductors 3 and 4t, through springs l) l)"', respectively,lightning-arrest ers 1 l, springs (i (1, connection-terminals Z and Y,and the linecircuit connected to Z and Y; fourths, from conductor 2,through spring on the left of Fig. 4, thermal protector L, ears J J,springG, liglnming-arresterl ,spring l), and conduetm'iii, and, lifth,from conductor 5, through spring (,f on the right of Fig. 4t, thermalprotector L, ears J J, spring G, lightning-arrester 1, spring l), andconductor 41. It will be readily seen that this arrangement provides asimple and ellicient means for testing the switchboard-circuit, the.

line through the heat-coils, the line direct, or either heat-coilseparately and independently of each other. ,lVhile I have traced outmetallic circuits for the line and switchboard testing, it is evidentthat grounded-return or common-return circuits may be equally tested. lntesting between conductors 2 and 3 or be tween conductors at and 5 thethermal protectors and their contacts with their supporting means aloneare tested as in actual service. Then the test-plug is withdrawn fromthe protective apparatus, contact-springs l. .l. again engage therespective protectors L L, as originally, and thereby automaticallyrestore the said apparatus to its operative condition.

In Fig. 4:, on each side of the ground-plate A A, l mount analarm-springI! between the line-spring (j and the mounting-strip A andadapt same to make contact with both the strip A. and spring (3r whendepressed. 1 provide an insulating-pin ll, extending through the springG ,adapted to normally hold springs (1i and 1? apart and to depressspring F when a thermal protector operates. hen the latter operationtakes place, spring E is released by the protective device L, asdescribed above, and comes in contact with the insulating-pin ll, whichthereupon depresses spring 11", first causing contact F thereof to makecontact with the ground-strip A and then still further depressing springF with contact F as a fulcrum until contact F makes connection withline-spring (1i. it will be readilyseen that by the operation of thethermal protector spring F closes an alarm-circuit between contact I?and ground-strip A and connects the line-spring (i to ground.-

In Fig. 5 I nel'erably employ a common alarm-strip. (Best showninFig.7.) I prefer this form of arrangement for closing an alarmcircuit overan individual spring for each set of the protective apparatus, as itdoes away with many separate parts and eliminates the necessity ofconnecting the alarmsprings logether by a common conductm, as is usuallydone. With this arrangement l. employ only two individual springs ineach set of the protective apparatus for supporting the proteetivedevices, for operating the thermal protector and eoi'ltrolling theseveral circuits, for testing purposes, as described, and for t| |econnection -ter1ninals, whereas it is the usual practice .to employ liveor six imlividual springs in each set of the protective appara: tus foraccomplishing all of these purposes. The alarm-strip A" is preferablymade of a very thin strip of metal, one side of which is punched, so asto provide a series of projecting portions ll" thereon. .lCachprojecting portion T is split at its free end and a portion turned up,as at U*, thus providing two contact portions V V on the straight partof T and a contact U on the turnedup portion thereof. 1 mount one of thealarm-strips A llatwise on each sideof the ground-plate A A, preferablyby bolts or rivets S, extending through the plate A A and holesT T ofthe alarm-strips, and insulate the latter from the plate A A byrespective insulating-strips it it, preferably as in Fig. l lach connmtU of alarm-strip A extends freely through a. hole in a line-spring i andis normally out of contact with the latter. lontarts V" V are alsonormally out of contact with groundstrip A, as shown upon the left-handside of Fig. When a thermal protector operates, it causes theswitchboanl-spring it to engage an insulating-pin ll, which extendsthrough the liuespring (i and thereby cause pin H to depress a tongueportion T" of alzn'ni-strip A, and thus cause contacts V V to engage theground-strip A and contact U to engage the lll'lO-Spl'lllg U, as shownupon the right of Fig. It will readily be seen that when a tongue T ofstrip A" is depressed, as described, it closes a circuit between thestrip A and grouml-strip A at contacts V V, which circuit may be analarm-circuit, and also connects its adjacent line-spring ii to groundthrough contact U and contacts V V".

\Vhile l have shown and described particular details of construction inthis ix'ivei'ition, 1 do not wish to limit same to such exact details,as slight modifications in certain parts of the structure would not be adeparture from the scope of the invention; l'lOltllUl do I wish to limitmyself to any particular type of thermal protector orlightning-arrester.

l-liaving thus described my invention, what I claim as new, and desireto secure by Letters Patent, is-

1.. In electric protective apparatus, the combination of a plate, a pairof springs mounted thereon, a protective device electrically con nectedwith one said spring and normally engaged by the other, and means forgrmnuling a spring, the said device being adapted to disengage one ofthe said springs therefrom under abnormal conditions, to ground theother sprin 2. In apparatus of the class specified, a

ground-plate, a pair of springs mounted thereon, means for grounding aspring, and a protective device electrically connecting the said springsbut adapted to operate under abnormal current conditions to disengageone of the said springs therefrom and allow same to spring toward theground-plate and ground the other said spring.

3. In electric protective apparatus, the combination of a ground-plate,a pair of superposed springs mounted thereon and insulated from eachother, means for grounding one of the springs, and a protective deviceadapted to disengage the outer spring therefrom and cause same tooperate and thereby ground only the inner spring of the pair, underabnormal circuit conditions.

4. In electric protective apparatus, a ground-plate, a pair ofsuperposed springs mounted thereon, a thermal protector mounted on theinner spring of the pair, the said protector and springs being normallyin a series circuit, and means operated by the outer spring whendisengaged from the protector and allowed to spring toward the innerspring,

to ground only the latter spring of the pair.

5. In electric protective apparatus, the combination of a sheet-metalmounting-plate, mounting-bolts extending through said plate near oneedge thereof, a pair of springs for each side of said plate and mountedthereon by said bolts, the said springs being line and switchboardterminals, respectively, a protective device for each pair of springsand adapted to be operated thereby, and a lineterminal and aswitchboard-terminal being crossed over to respective opposite sides ofthe mounting-plate, past one edge thereof, for the purpose of arranginglike terminals together, substantially as described.

6. In electric protective apparatus, the combination of a mounting-platecomprising thin strips of sheet metal secured to each other at one edgeand held a slight distance apart over the remainder of the plate, aseries of mounting-bolts extending through said plate near the open edgethereof, suitable d istance-pieces placed between the sheet-metal stripsat the said bolts, series of spring members mounted upon opposite sidesof said plate by said bolts,

ed upon one side of said plate and suitably insulated from each other, aprotective devicefor each pair of springs and normally connectedtherewith, a common strip mounted on said plate between the said pairsof springs and the ground-plate, and suitably insulated, and meanswhereby the operation of a protective device causes the said commonstrip to connect a spring of one pair with the groundplate.

8. In protective apparatus for electric circuits, a ground-plate, aseries of pairs of springs suitably mounted upon one side of said plateand insulated therefrom and from each other, a protective device foreach pair of springs, mounted on one spring of the pair and adapted tobe engaged by the other, and. a common strip suitably mounted andprovided with a series of tongue portions any one of which is adapted toconnect a spring of a pair with the ground-plate when a protectivedevice operates.

9. In apparatus of the class specified, a ground-plate, a series ofline-springs mounted thereon and insulated therefrom, a series ofswitchboard-springs also mounted thereon and insulated from theline-springs, a protective device for each pair of springs and mountedon the line-spring of the pair, a series of lightning-arresters placedbetween the free ends of the line-springs and the ground-plate,

apparatus also mounted thereon, and means whereby the operation of anyone of the sets of protective apparatus brings a contact portion of thealarm-strip in contact with the ground-plate and thereby closes analarm-cireuit.

11. In protective apparatus for electric circuits, a sheet-metalgroundplate, a common alarm-strip for each side of said plate, mountedthereon and insulated therefrom, a series of sets of protectiveapparatus for each side of the said plate and mounted. thereon outsideof the respective alarm strips, and means whereby the'operation of a setof the protective apparatus'causes the corresponding alarmstrip to closean alarm-circuit between itself and the ground-plate and ground aspringof the set.

12. In electric protective apparatus, the combination of a ground plate,a pair of springs mounted thereon, a thermal protector mounted on onesaid spring and adapted to be engaged by the other, an alarm-spring, and

means included by the protector whereby the operation of the latterdisengages one of the said springs therefrom and allows same to operateand cause the alarm-spring to close an alarm-circuit and ground theother said spring of the pair.

13. .In electric protective apparatus, the combination of a groundplate, a pair of springs mounted thereon, a thermal protector mounted onone said spring and adapted to be engaged by the other, an alarm-springmounted between the pair of springs and the g roundplate, and meansincluded by the protector whereby the operation of the latter disengagesone of the said springs therefrom and allows same to operate and causethe alarmspring to make contact with the ground-plate and the otherspring of the pair, thereby closing an alarm-circuit and grounding thelast-mentioned spring of thevpair, substantially as described.

'14.. In electric protective apparatus, the combination of asupporting-plate, a pair of springs mounted thereon, a thermal protectorconductively mounted on one said spring and adapted to be engaged by theother, and means included by the latter said spring with which atest-plug cooperates to disengage said spring from the protector whiletesting.

15. In electric protective apparatus, the combination of amounting-plate, a pair of spring members mounted thereon, a thermalprotector conductively mounted on one said spring and adapted to beengaged by the other, and a testing means adapted to engage theprotective device and the last mentioned spring and in so doing to openthe circuit between the latter and the protective device, for testing.

16. In electric protective apparatus, the combination of amounting-plate, a pair of superposed swings mounted thereon, a thermalprotector mounted on one said spring and normally engaged by the other,a hole in the latter said spring adapted to receive a testplug andthereby open the circuit through the protector, and means adapted toengage the protector for testing.

17. In electric protective apparatus, the combination of amounting-plate, a pair of spring members for each side thercol andmounted thereon, a thermal protector for each pair of springs,conductively mounted on one spring of its pair and adapted to be engagedby the other spring of the pair, and means included by the latter saidsprings with which a test plug co( perates to disengage said springst'rom the respective protectors for testing.

18. .In electric protective apparatus, the combination of an'lounting-plate, a pair of springs for opposite sides thereof andmounted thereon, a thermal protector for each pair of springs, eachbeing conductively mounted on one spring and adapted to be engaged byanother, and a testing means adapted to en gage the protective devicesand the said engaging springs of the pairs and in so doing to open thecircuits between the latter said springs and their respective protectivedevices, substantially as described.

19. In electric protective apparatus, the combination with amounting-plate, ot' a pair of superposed springs for opposite sidesthereof and mounted thereon, a thermal protector mounted on one saidspring 01' each pair and normally engaged by the other, a hole in theengaging spring of each pair adapted to receive a test-plug and therebyopen the circuits through the protectors, and means adapted to engagethe protectors also, for testing, substantially as described.

20. In amiaratus ot' the class specified, the combination of amounting-strip, a protective device for each side of said strip andsuitably mounted, a spring for each said device and normally engagingsame, and an aperture in each said spring through which contact membersof a testing-plug are inserted for testing, the said insertion causingthe said springs to disengage the said devices, For purposessubstantially as described.

21. In apparatus of the class specilied, the combination ol amounting-plate, a protective device for each side thereol and suitablymounted, an engaging means for each said device and normally engagingsame, an aperture in each engaging means, and contact members of atest-plug adapted to be inserted through said apertures, and to engagesaid devices, respectively, and by such connection to disengage the saidengaging means from their respective protective devices, for purposessubstantially as described.

22. In protective apparatus for electric circuits, the combination of aground-plate comprising parallel sheet-metal strips properly secured toand spaced from each other over respective portions of same, a commonalarm strip for each side of said plate and insulatively securedthereto, a series of projecting contact members on each alarm-strip, aseries of pairs of superposed springs for each side of the ground-mate,mounted flatwise thereon and insulated therefrom and from each other,mounting-bolts for the said springs and extending through the rear edgeoi the groundplate, lightning-arresters inserted between the respectiveinner springs of the pairs and the ground-plate, heat-coils cond uctively mounted on the respective inner springs of the pairs, a contactportion on each outer spring oi the pairs and adapted to engage therespective heat-coils, an aperture in each outer spring of the pairs andadapted to receive respective contact members of a testing'plug, aninner spring and an opposite outer spring of each oppositely-mountedpairs of springs being crossed over to opposite sides of the groundplatethrough space at the rear of same, for

the purpose of arranging like connection-ten minals on the same side ofthe ground-plate, an insulating-pin extending through each inner springof the pairs, through the agency of which the said outer springs depressthe respective projecting contact members of the alarm-strips when therespective heat-coils operate, the operation of a heat-coil allowing itssaid outer spring to release itself and thereby open the circuit throughthe heat-coil, close an alarm-circuit and ground the inner spring of thepair, and contact members of'a testingplug adapted to engage therespective apertures in the outer springs of an oppositelymounted pairof the protective apparatus, and the heat-coils of same, respectively,and to disengage the said outer springs from the respective heat-coilswhen thus inserted, substantially as described.

23. In apparatus of the class specified, the combination of amounting-plate, a pair of springs mounted thereon, a thermal protectorconductively mounted on one said spring and engaged by the other, andmeans With which a test-plug cooperates to disengage the said engagingspring from the protector for testing.

24. In apparatus of the class specified, a thermal protector, means forengaging the protector and tending to operate same, and means fordisengaging the said engaging means from the protector for testingpurposes.

25. In apparatus of the class specified, a thermal protectorconductively mounted on a suitable support, a conducting member normallyengaging the protector and in circuit with the latter and said support,and means for opening the said circuit for testing the apparatus.

26. In combination, a thermal protector, a conductive portion engagingthe protector and adapted to operate under abnormal conditions, andmeans whereby the said conductive portion may be disengaged from theprotector for testing the apparatus or through the apparatus.

27. In combination, a thermal protector, a spring member adapted toengage a portion of the protector and to operate upon an abnormalcurrent in the latter, and means for disengaging the spring member fromthe protector to open the circuit through same for testing.

28. In combination, a thermal protector for electric circuits, a springmember adapted to engage a portion of the protector and to operate tocontrol a circuit When the protector gives Way, and means fordisengaging the spring member from the protector and for engaging theprotector and spring member for testing, substantially as described.

29. In apparatus of the class specified, a pair of spring members, athermal protector conductively mounted on one spring member and normallyengaged by the other, and means for grounding a spring member; abnormalcondi' ed to operate and operate the protector to disengage itselftherefrom, under abnormal cond1t1ons, and by such operation cause thesaid conducting member to be grounded.

31. In apparatus of the class specified, asupporting-plate, a thermalprotector suitably mounted in a fixed position relatively to the plate,and a spring member normally engaging the protector but adapted todisengage itself therefrom, under abnormal conditions, and operatetoward the supporting-plate to control a circuit.

32. In electric protective apparatus, the combination of amounting-plate, a pair of springmembers for each side of the plate andsuitably mounted thereon, the said springs being line and switchboardterminals, respectively, a protective device for each pair of springsand adapted to cooperate therewith, and a line-terminal and aswitchboard-terminal being crossed over to respective opposite sides ofthe mounting-plate past one edge thereof, for the purpose of arranginglike terminals together, substantially as described.

33. In electric protective apparatus, the combination of amounting-plate, a pair of spring members for each side of the plate,suitably mounted thereon and one spring of each pair having an endportion thereof crossed over to the opposite side of the plate past theedge thereof, and a protective device for each pair of springs andadapted to cooperate there- With, for purposes substantially asdescribed.

34:. In electric protective apparatus, a plate,

conducting members for each-side of the plate,

mounted thereon and a conducting member of each side of the plate havingan end portion thereof crossed over to respective opposite sides of theplate to form terminals for circuit-conductors, and a protective devicefor each side of the plate and arranged to cooperate With the saidconducting members in the use of the apparatus, substantially asdescribed;

35. In electric protective apparatus, a ground-plate, a pair of springsmounted thereon, a protective device rigidly mounted on one said springin a fixed position relatively to the ground-plate, and normally engagedby the other, and an alarm-spring adapted to be operated by the saidengaging spring becoming disengaged from the protective device, tocontrol an alarm-circuit.

36. In electric protective apparatus, a ground-plate, a conductingmember and a spring member mounted on the ground-plate, aprotectivedevice mounted on the said conducting memhcr in a fixed positionrelatively to the ground-plate, and engaged hy the said swing, and meansfor closing an alarm-circuit actuated by the said spring becoming disengaged from the protective device.

37. In electric protective apparatus, a groundplate, a pair ofsuperposed springs suitablymounted on the said plate, a protectivedevice mounted on the inner spring of the pair and engaged hy theouterspring, and an alarm-spring interposed hetwcen the pair of springsand the grouml-plate and hronght in contact with the ground-plate hy theouter spring of the pair when same is released from the protectivedevice, to close an alarm-circuit.

38. In electric protective apparatus, 'a grouml-plate, a pair ofsuperposed springs suitably mounted on the said plate, a protectivedevice rigidly mounted on the inner spring of the pair and normallyengaged by the outer spring, and an alarn'i-spring interposed hetweenthe pair of springs and the groundplate and adapted to he operated bythe outer spring of the pair when same is disengaged from the protectivedevice, to close an alarmcircuit and ground the inner spring of thepair.

Si). in electric protective apparatus, a mounting-plate, a pair ofsprings mounted thereon, a thermal protector mounted on the inner springof the pair and normally engaged by the outer spring, the latter springheing adapted to release itself from the protector and operate towardthemounting-plate under ahnormal conditions, means for rei'mgaging theengaging spring with the protector to reset the apparatus, and means forswinging the said engaging spring away from thei mounting-plate todisengage it from the protector for testing purposes.

40. in electric protective apparatus, a mounting-plate, a thermalprotector suitably mounted. a s iring member mounted on the said plateand adapted to engage the protector, ahnormal conditions in the latterallowing same to release the said spring therefrom, means for reengagingthe latter with the pro teeter to reset the device, and means fordisengaging the said spring from the protector to test the apparatus.

41. in comhination, a thermal-protector adapted to he included in acircuit, means for engaging the protector and adapted to operate underahnormal conditioi'is to control a circuit, and means for disengagingsaid engag ing means from the protector for testing purposes.

42. in comhination, a thermal protector adapted to he included in acircuit, a spring memher for engaging the protector and adapt ed todisengage itself therefrom and operate in one direction to open thecircuit through the device, upon an ahnormal current therein, means forreengaging the spring memher with the protector to resettheapparatus,and means for operating the spring meinher in the opposite directiontodisengage same from the protector and open the circuit through thelatter for testing.

As inventor of the foregoing l hereunto suhscribe my name, in thepresence of two witnesses, this 7th day of July, A. l). 1904.

